Optolong Luminance (L) filter can be used with RGB filters or used as UV/IR cut filter.

Highlights

• 95% transmission at passband
• Multi-layers anti-reflection coating
• Precise and sharp roll-off at off-band
• Infrared cut-off at 700-1100 nm
• 2 mm filter thickness
• Made on Schott substrate
• Finely polished to 1/4 wave accuracy
• Surface quality: 60/40 (MIL-O-13830 standard)
• Equal weighting factor can be used for each channel, useful for automated imaging system

Recommended applications

• UV / IR cut filter for camera with AR only optical windows
• Monochrome CCD/CMOS camera
• Deep sky and planetary colour imaging

Available in sizes

• 1.25" (26mm clear aperture)
• 36mm round unmounted
• 2" (45mm clear aperture)

Coating technologies

• Multi layers anti-reflection coating
• Non cementing optical substrate coating
• Electron-beam gun evaporation with ion-assisted deposition coating technology to enhance coating durability and resistance to scratching as well as stability on central wavelength such that passband does not deviate with temperature change
• Planetary rotation system offers high precision and homogeneity of coating surface ensuring high value on passband transmission and off-band blocking. 

Filter cell technologies

• CNC machined with aerospace grade aluminium
• Black anoidised finish and extinction treatment to prevent refection
• Laser engraved fade-free wordings 

We care about delivering your filter in perfect form and thus every Optolong filter sits on a high density sponge carton lining and packaged in highly rigid plastic PP case with high pressure EVA case lining. 

User gallery

Terry Hancock

User Reviews

1. Cloudynights: Optolong LRGB Filter Testing & Comparison with Baader LRGB filters by Terry Hancock

About Optolong

Optolong is a brand dedicated for astronomical filters R&D and production under Kunming Yulong Optical & Electronics Technology Co. Ltd. Yulong is a professional manufacturer of high quality filters since 1999. Yulong has passed ISO9001 quality certifcation and all products meet ROHS standard authorised by SGS test. 

Their major equipment include ultra clean room, five precise vacuum coating machines, Shimadzu UV-VIS-NIR spectrophotometer, 12 sinks ultrasonic cleaning machines and grinding/rolling/cutting machines.

Optolong filters only use the best glass — German's Schott glass as the substrate which has an industry leading level of flatness which is crucial to minimise the occurence of halo and ensure high quality image.